ACSLite

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• ACS-Lite
• Adaptive Control Software for Closed-loop Traffic
  Control Systems
• Raj Ghaman, P.E.
• Operations Team Leader
• FHWA RDT

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Adaptive in the U.S. (FHWA)

• 1970s-1980s UTCS / TRPS
• Second by second central
• 1990s Predictive control (ACS)
• FHWA ACS RHODES, OPAC, RTACL
• Second by second distributed
• 2002 Controller-based Adaptive
• FHWA ACS Lite
• Leverage existing hardware / infrastructure
• Download new controller parameters every
  five-fifteen minutes

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FHWA Goals for ACS-Lite

• Low cost design
• Leverage existing infrastructure
• Standard US-style actuated controllers and logic
  (rings, phases, splits, barriers,
  gap-out/extension, etc.)
• Standard fully-actuated detector layouts
• Standard NTCIP Communications
• Retro-fit with major US signal system vendors

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Project Team
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Field trials
Econolite Gahanna (Columbus), Ohio
McCain El Cajon (San Diego), California
Eagle/Siemens Houston, Texas
Peek/Quixote Bradenton (St. Petersburg/Tampa),
Florida
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Gahanna, OH field test results
Results - Number of Stops
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Gahanna, OH field test results
1Peak hours Average savings(Average Corridor
Peak Hour Volume4 peak hours)

• Unit Costs
• Total Delay 12.10 per hour
• Stops 0.014 per stop
• Fuel Consumed 0.59 per liter (2.25 per gallon)

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Houston, TX field test results
Results - Travel Time
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Houston, TX field test results

• Unit Costs
• Total Delay 12.10 per hour
• Stops 0.014 per stop
• Fuel Consumed 0.59 per liter (2.25 per gallon)